package com.fangjc1986.support.util;

import org.apache.tomcat.util.codec.binary.Base64;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * @version V1.0
 */
public class AESUtil {

    private static final String KEY_ALGORITHM = "AES";
    private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";//默认的加密算法
    private static final String PASSWORD = BeanUtil.getParamsUtil().getAesSecret();

    /**
     * AES 加密操作
     *
     * @param content  待加密内容
     * @param password 加密密码
     * @return 返回Base64转码后的加密数据
     */
    public static String encrypt(String content, String password) {
        try {
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 创建密码器
            byte[] byteContent = content.getBytes("utf-8");
            cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(password));// 初始化为加密模式的密码器
            byte[] result = cipher.doFinal(byteContent);// 加密
            return Base64.encodeBase64String(result);//通过Base64转码返回
        } catch (Exception ex) {
            Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
        }

        return null;
    }

    /**
     * 快捷加密
     *
     * @param content 加密内容
     * @return
     */
    public static String encrypt(String content) {
        return encrypt(content, PASSWORD);
    }

    /**
     * AES 解密操作
     *
     * @param content  解密内容
     * @param password 密码
     * @return
     */
    public static String decrypt(String content, String password) {
        try {
            //实例化
            Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
            //使用密钥初始化，设置为解密模式
            cipher.init(Cipher.DECRYPT_MODE, getSecretKey(password));
            //执行操作
            byte[] result = cipher.doFinal(Base64.decodeBase64(content));
            return new String(result, "utf-8");
        } catch (Exception ex) {
            Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
        }
        return null;
    }

    /**
     * 快捷解压
     *
     * @param content 解密内容
     * @return
     */
    public static String decrypt(String content) {
        return decrypt(content, PASSWORD);
    }

    /**
     * 生成加密秘钥
     *
     * @return
     */
    private static SecretKey getSecretKey(final String password) {
        //返回生成指定算法密钥生成器的 KeyGenerator 对象
        KeyGenerator kg = null;
        try {
            kg = KeyGenerator.getInstance(KEY_ALGORITHM);
            SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG");
            secureRandom.setSeed(password.getBytes());
            kg.init(128, secureRandom);
            return kg.generateKey();
            //AES 要求密钥长度为 128
            //kg.init(128, new SecureRandom(password.getBytes()));
            //生成一个密钥
            //SecretKey secretKey = kg.generateKey();
            //return new SecretKeySpec(secretKey.getEncoded(), KEY_ALGORITHM);// 转换为AES专用密钥
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
        }
        return null;
    }

    public static void test() {
        System.out.println(PASSWORD);
    }

    //public static void main(String[] args) {
    //    String s = "hello,您好";
    //    System.out.println("s:" + s);
    //    String s1 = AESUtil.encrypt(s, "1234");
    //    System.out.println("s1:" + s1);
    //    System.out.println("s2:" + AESUtil.decrypt(s1, "1234"));
    //}

}
